In the last decade, methamphetamine (METH) use has been correlated with a rising incidence of HIV-1 infection. Furthermore, the reported cases of rapidly progressive HIV-1 infection in METH users underscore the importance of determining the influence of METH on infection of the CNS by HIV-1. The purpose of this grant is to test the hypothesis that METH (and possibly other psychostimulatory drugs) enhances the development of antiviral drug resistant mutants of HIV through a process that accelerates the frequency of infection events, and the concomitant incidence of reverse transcription errors. The emergence of drug resistant genotypes of HIV is prone to take place in the central nervous system (CNS) where drug concentrations may be suboptimal for the effective control of HIV replication. At the same time, the CNS is thought to be under less surveillance by the immune system because of restrictions in T-cell trafficking created by the blood-brain-barrier (BBB). Thus, the CNS serves as a privileged site for HIV infection, replication, adaptation and selection. Furthermore, the CNS may be a reservoir for drug-resistant variants that can enter the peripheral compartment. The proposal has two Specific Aims. Specific Aim 1 is to test the hypothesis that METH accelerates the development of drug-resistant lentiviruses in vitro. This Aim has four objectives: #1: Compare the rate of development of AZT resistant FIV for astrocytes and microglia cultured in the presence or absence of METH. Objective #2: Compare the rate of development in vitro of AZT-resistant HIV for astrocytes and microglia cultured in the presence or absence of METH. Objective #3: Measure the effect of METH on inflammatory cytokine production by uninfected and lentivirus-infected lymphocytes, astrocytes and microglia and correlate with virus expression in these cell types. Objective #4: Determine if METH enhances HIV infection of human target cells, promotes cell proliferation and modulates CXCR4 and/or CCR5 expression. Specific Aim #2 is designed to test the hypothesis in vivo via a proof-of-principle study in the FIV/cat system to evaluate the effect of METH on the development of AZT resistance in vivo. The prospect that psychostimulatory drugs, which include a broad range of legal and illegal substances, can alter the pathogenesis of HIV and influence the emergence of drug-resistant variants is novel. The idea that HIV sequestered in the CNS may have more latitude to become drug-resistant has been proposed previously, but the possible role of METH in this process is a new aspect of that concept. PROJECT NARRATIVE: The CNS is a reservoir for lentivirus infection that is distinct from the peripheral compartment and that allows for the independent evolution of virus variants, especially antiviral drug resistant mutants. Based on our observations, we hypothesize that METH may potentiate the development of drug resistant viruses in the CNS, which then can enter the peripheral compartment. The recent report of a rapidly progressive, highly drug resistant HIV-1 infection in a METH user in New York underscores the importance of elucidating the interactions between METH and HIV-1 and the development of drug resistance in the CNS. In addition, METH is one of several psychotropic drugs that may have similar effects on HIV infection of the CNS. The possibility that psychotropic drugs may accelerate the development of antiviral drug resistance in HIV-infected people is an important public health concern. [unreadable] [unreadable] [unreadable]